Could diesel locomotives cause more global waming than what steam locomotives did?

[778]

Could diesel powered trains (locos and DMU'S) actually cause more global warming than steam locomotives?

Coal fired steam locomotives do produce a lot of CO2 emissions but also aerosols which has a cooling effect (global dimming), which cancels out some of the warming produced by CO2. Diesel locos probably produce less CO2 but also less aerosols that would cancel out the CO2.

Global temperature only started rising in the 70s after most countries in the world replaced steam locomotives with diesels and the clean air act was passed. Reducing aerosols and cleaning the air is still a good thing, but it could mean that global temperatures are rising more, because aerosols could have masked a lot of the warming caused by greenhouse gasses.

I am not saying that steam locomotives were especially good for the environment, more that they did not really cause global temperatures to rise.

 

[diffident]

It's surely six of one and half a dozen of the other isn't it?

 

[hexagon789]

Could diesel powered trains (locos and DMU'S) actually cause more global warming than steam locomotives?

Coal fired steam locomotives do produce a lot of CO2 emissions but also aerosols which has a cooling effect (global dimming), which cancels out some of the warming produced by CO2. Diesel locos probably produce less CO2 but also less aerosols that would cancel out the CO2.

Global temperature only started rising in the 70s after most countries in the world replaced steam locomotives with diesels and the clean air act was passed. Reducing aerosols and cleaning the air is still a good thing, but it could mean that global temperatures are rising more, because aerosols could have masked a lot of the warming caused by greenhouse gasses.

I am not saying that steam locomotives were especially good for the environment, more that they did not really cause global temperatures to rise.

It also depends what they were burning - many countries used oil rather than coal firing. Or in some cases wood.

Also in general fewer diesels were needed to replace steam locos.

There is the oft-bandied figure of 22 Deltics replacing 55 Pacific-type steam locos for example.

 

[mikeg]

Also it depends on the thermal efficiency of the engine. Steam cycles generally have pretty poor efficiency even in modern day coal power stations much less than 50 percent of heat generated becomes electricity. Ironbridge for example has a thermal efficiency of about 33 percent. I imagine a steam engine would be even less efficient but am happy to be proven wrong. Not that diesel engines are particularly brilliant in this respect either. In fact just looked it up and they're pretty similar so really does depend on whether steam on a locomotive performs better or worse than a power station, my suspicion is much worse.

 

[zwk500]

There's a few other factors at play in global temperatures than what type of loco was used! The key factor in the early 70s was not Steam to Diesel transition but the Industrialisation of East Asia, and the expansion of Motor Car use. You can't judge Steam vs Diesel environmental impact using the global average temperature, as rail is a small part in the direct production of emissions. (The environmental impact of rail's transport function by facilitating economic development/resource extraction is a separate discussion from traction type).

As a small point, it's also worth pointing out that 1 diesel replaces 2-3 Steam locos, so there's a reduction in the Emissions created producing the locomotives, as well as a reduction in non-revenue moves and a reduction in maintenance requirements producing emissions.

 

[E27007]

Also it depends on the thermal efficiency of the engine. Steam cycles generally have pretty poor efficiency even in modern day coal power stations much less than 50 percent of heat generated becomes electricity. Ironbridge for example has a thermal efficiency of about 33 percent. I imagine a steam engine would be even less efficient but am happy to be proven wrong. Not that diesel engines are particularly brilliant in this respect either. In fact just looked it up and they're pretty similar so really does depend on whether steam on a locomotive performs better or worse than a power station, my suspicion is much worse.

It is said that for every ten shovels of coal into the firebox, only one is the work of moving a load.
Smoke emissions, you could locate a steam shed from afar by the dark cloud of soot and smoke in the sky

 

[contrex]

Also it depends on the thermal efficiency of the engine. Steam cycles generally have pretty poor efficiency even in modern day coal power stations much less than 50 percent of heat generated becomes electricity. Ironbridge for example has a thermal efficiency of about 33 percent. I imagine a steam engine would be even less efficient but am happy to be proven wrong. Not that diesel engines are particularly brilliant in this respect either. In fact just looked it up and they're pretty similar so really does depend on whether steam on a locomotive performs better or worse than a power station, my suspicion is much worse.

I read recently that Chapelon pacifics were considered exceptional at 12%

 

[DarloRich]

surely the difference, in the grand scheme of things, will be tiny

 

[tellytype]

No becasue the whole thing is a load of piffle anyway

 

[stuu]

Could diesel powered trains (locos and DMU'S) actually cause more global warming than steam locomotives?

Coal fired steam locomotives do produce a lot of CO2 emissions but also aerosols which has a cooling effect (global dimming), which cancels out some of the warming produced by CO2. Diesel locos probably produce less CO2 but also less aerosols that would cancel out the CO2.

Global temperature only started rising in the 70s after most countries in the world replaced steam locomotives with diesels and the clean air act was passed. Reducing aerosols and cleaning the air is still a good thing, but it could mean that global temperatures are rising more, because aerosols could have masked a lot of the warming caused by greenhouse gasses.

I am not saying that steam locomotives were especially good for the environment, more that they did not really cause global temperatures to rise.

Railway operations are a trivial percentage of emissions, they would have only ever contributed at the margin to climate change. As has been pointed out already, steam locomotives are incredibly inefficient, burning the coal in a power station and turning it into electricity is far more sensible

 

[ac6000cw]

I read recently that Chapelon pacifics were considered exceptional at 12%

Yes, they were. Based on what I've read, 6% average thermal efficiency was more typical for steam locomotives. For comparison, a modern AC-traction drive diesel is around 35% efficiency, older DC-drive diesels were maybe around 25%.

 

[DanNCL]

Global temperature only started rising in the 70s after most countries in the world replaced steam locomotives with diesels and the clean air act was passed. Reducing aerosols and cleaning the air is still a good thing, but it could mean that global temperatures are rising more, because aerosols could have masked a lot of the warming caused by greenhouse gasses.

I think the timing is a coincidence. The then-new mass use of Jet airliners, the the Space Race, and the further expansion of industrialisation are much more likely to be the main cause.

 

[ac6000cw]

There's a few other factors at play in global temperatures than what type of loco was used! The key factor in the early 70s was not Steam to Diesel transition but the Industrialisation of East Asia, and the expansion of Motor Car use. You can't judge Steam vs Diesel environmental impact using the global average temperature, as rail is a small part in the direct production of emissions. (The environmental impact of rail's transport function by facilitating economic development/resource extraction is a separate discussion from traction type).

As a small point, it's also worth pointing out that 1 diesel replaces 2-3 Steam locos, so there's a reduction in the Emissions created producing the locomotives, as well as a reduction in non-revenue moves and a reduction in maintenance requirements producing emissions.

I agree, and rising world population and living standards (the energy needs of which was largely met by fossil fuels, coal particularly, either used directly or burnt to generate electricity).

 

[InTheEastMids]

I agree, and rising world population and living standards (the energy needs of which was largely met by fossil fuels, coal particularly, either used directly or burnt to generate electricity).

Tiny in the grand scheme of things as all the non-railway world switched on their lights and got in their cars thanks to fossil fuels.

There is the oft-bandied figure of 22 Deltics replacing 55 Pacific-type steam locos for example

Imagine the railway had stuck with comparatively inefficient steam ops, then it's easy to imagine more railways would have closed, leading to more modal shift to road and even more emissions.

also aerosols which has a cooling effect (global dimming)

Perhaps, but...

Smoke emissions, you could locate a steam shed from afar by the dark cloud of soot and smoke in the sky

...it's a trade-off of effects. The local air quality impacts of combustion on environment, health are also very important (see link). It's really hard to envisage a world where the UK progressively tightened the law around other kinds of air pollution e.g. from domestic fires (I think the first was the Clean Air Act 1956) but were completely fine about steam trains. I personally doubt it'd have been feasible to put the kind of exhaust cleanup on a steam locomotive that you'd find on a coal-fired power station.

Health matters: air pollution

www.gov.uk

[Link to UK government web page on health impacts of air pollution]

 

[zwk500]

but also aerosols which has a cooling effect (global dimming), which cancels out some of the warming produced by CO2. Diesel locos probably produce less CO2 but also less aerosols that would cancel out the CO2.

Global temperature only started rising in the 70s after most countries in the world replaced steam locomotives with diesels and the clean air act was passed. Reducing aerosols and cleaning the air is still a good thing, but it could mean that global temperatures are rising more, because aerosols could have masked a lot of the warming caused by greenhouse gasses.

I am not saying that steam locomotives were especially good for the environment, more that they did not really cause global temperatures to rise.

It's important to understand that the problem is climate *Change*, not specifically warming or cooling. A volcanic winter from Aerosols would be just as devastating to life on the planet as Global warming of 2 degrees. The 1880s Krakatoa eruption is thought to have pumped so much ash into the air that it depressed harvest yields globally and caused famine in a number of areas around the world. At least Volcanic ash is fertile, coal dust doesn't even give you that compensation.

 

[al78]

Global temperature only started rising in the 70s after most countries in the world replaced steam locomotives with diesels and the clean air act was passed.

This is false. Global temperature has been rising since at least the start of the 20th century and have been partially offset by aerosol emissions. Trends in surface air temperature due to anthropogenic forcing can be attributed as far back as the 1920's.

RealClimate: Watching the detections

RealClimate: The detection and attribution of climate change are based on fundamentally different statistical frameworks and shouldn't be conflated.

www.realclimate.org

It's important to understand that the problem is climate *Change*, not specifically warming or cooling. A volcanic winter from Aerosols would be just as devastating to life on the planet as Global warming of 2 degrees. The 1880s Krakatoa eruption is thought to have pumped so much ash into the air that it depressed harvest yields globally and caused famine in a number of areas around the world. At least Volcanic ash is fertile, coal dust doesn't even give you that compensation.

It comes down to the rate and magnitude of change, the possible/likely consequences of that change, and adaptability. You only have to look at the UK rail network to see how even small perturbations can cause major problems.

 

[43066]

I am not saying that steam locomotives were especially good for the environment, more that they did not really cause global temperatures to rise.

I would hope nobody would seriously try to suggest any type of locomotive has caused temperatures to rise - the contribution will be absolutely minuscule.

No becasue the whole thing is a load of piffle anyway

The whole thing is far too politicised which prevents a sensible debate. Nothing we do in this tiny country will have any real effect anyway. In my view we should accept the inevitable and rather than worrying about (and spending huge amounts on) “net zero” for the sake of virtue signalling we should get busy building flood defences.

 

[102 fan]

The problem is that governments look at this and just raise taxes, not for any environmental benefit but just to increase the Treasuries income.

And can it be denied that the current energy prices are partly a result of the environmental aims?

 

[InTheEastMids]

Nothing we do in this tiny country will have any real effect anyway.

Not true. The UK has been absolutely instrumental in making offshore wind one of the cheapest forms of electricity generation today.

A volcanic winter from Aerosols would be just as devastating to life on the planet as Global warming of 2 degrees.

True, but one of these issues is something people can do something about.

 

[zwk500]

True, but one of these issues is something people can do something about.

The point was that humans affect the climate in both ways. Maybe volcanic winter was the wrong choice, but human activity that shades the planet is just as big a threat of climate catastrophe as rising temperatues.

 

[randyrippley]

Diesels produce a heck of a lot more nitrous oxides than steam engines, but conversely steam - depending on the coal - will produce a lot more sulphate. Both have significant effects

 

[david1212]

It also depends what they were burning - many countries used oil rather than coal firing. Or in some cases wood.
......

Back in the 1970's the Ffestiniog converted some steam locos to using waste oil. I recall reading that the oil consumption of these, admittedly far from highly developed relatively fuel efficient designs, was several times higher than a diesel, again even for the era old technology.

...

Also in general fewer diesels were needed to replace steam locos.

There is the oft-bandied figure of 22 Deltics replacing 55 Pacific-type steam locos for example.

Without getting deep into the finer detail of maintenance and inspection regimes a Deltic potentially could run 2 London <> Edinburgh and 2 London <> Newcastle trips in a day allowing 1 hour turnaround for refuelling.
For steam what would the fastest reasonable turnaround be ? As well as refilling the tender with coal there was at least emptying the ash pans and smokebox.

Directly relevant to efficiency and global warming while not quite switch on and go a Deltic or any other diesel could be hooked up ready to go far quicker than steam as the boiler full of water had to be heated. At the end of the day the remaining water would cool again. The energy that had earlier been used this water is waste. While boilers had lagging when idle there still must have been significant heat and hence energy loss. A diesel could be shut down between duties although often left in reality left idling.

Overall I find it hard to see that relatively diesel locos contributed more to global warming than coal fired steam.

 

[DerekC]

What matters for climate change is the carbon dioxide emissions per drawbar kWH (or drawbar horsepower hour) and there is absolutely no doubt that diesel beats steam hands down. Steam locomotives have a thermal efficiency of between 6% and 12%. Diesel locomotives have a thermal efficiency of 20 - 25%. Then you have to take account of the carbon content of the fuel. Bituminous coal and diesel oil both emit about 0.25 kg of CO2 per kWH of heat generated, so in fact that factor doesn't make much difference. So at first sight steam locos produce somewhere between twice and four times as much CO2 per drawbar kWh. But then you have to take account of the fact that a steam loco has to be lit up several hours before it starts duty and the fire has to be allowed to burn out or be dumped at the end whereas a diesel can more or less be started up when needed.

As far as the overall effect is concerned, steam locomotives probably represented a much bigger proportion of total CO2 emissions when railways were the dominant form of transport, but I guess it must represent a pretty small proportion of total man made CO2 emissions overall.

The people who think it's all rubbish or that what we do won't make any difference or that we should just build flood walls simply don't want to understand. Perhaps that's a comfortable place to be, but if you do understand you want to do something about it. And in railway terms that's quite obviously electrification. Subject of lots of other threads!!

 

[Bevan Price]

The thermal energy required to raise water temperature from ambient to boiling point - although necessary - is effectively "waste" when it comes to moving a train.. The only "useful" energy could be regarded as that needed to convert liquid water (at boiling point) to high pressure steam - since that is what is required to move a steam loco and its train. .

 

[DerekC]

The thermal energy required to raise water temperature from ambient to boiling point - although necessary - is effectively "waste" when it comes to moving a train.. The only "useful" energy could be regarded as that needed to convert liquid water (at boiling point) to high pressure steam - since that is what is required to move a steam loco and its train. .

That's right, but it should all be wrapped up in the way you calculate efficiency. You should take the total energy output at the drawbar divided by the total coal used for a steam loco operating a certain diagram, from cold boiler back to cold boiler, and compare it with the equivalent diesel figure. It's not easy - and some steam loco enthusiasts fiddle the figures by measuring only the coal consumption at a specific speed and power output for a specific time, which ignores all the wasted heat you are talking about. Of course electric traction has one fundamental advantage over both diesel and steam, which is that you can use regenerative braking to recover part of the kinetic energy put in when you accelerate the train and part of the potential energy when you climb a gradient.

 

[2192]

Most Locomotives spend most of their time standing still. Electrics & Diesels can be switched off, and brought to life again at short notice. Steam locos can't, and are producing CO2 whilst they are stationary. Electrics are best (once built) provided they get their electricity from renewable sources: wind, sun, wave, tide, hydro. These produce zero CO2.

 

[zwk500]

That's right, but it should all be wrapped up in the way you calculate efficiency. You should take the total energy output at the drawbar divided by the total coal used for a steam loco operating a certain diagram, from cold boiler back to cold boiler, and compare it with the equivalent diesel figure. It's not easy - and some steam loco enthusiasts fiddle the figures by measuring only the coal consumption at a specific speed and power output for a specific time, which ignores all the wasted heat you are talking about. Of course electric traction has one fundamental advantage over both diesel and steam, which is that you can use regenerative braking to recover part of the kinetic energy put in when you accelerate the train and part of the potential energy when you climb a gradient.

The problem with electric traction is the embedded carbon generated by the construction/reconstruction of the railway required to install the OLE and distribution gear. Electricity also still needs to be generated somewhere, regenerative braking just tops up, and the UK's mix isn't anywhere near net zero yet (although I do accept that a power plant, even coal-fired, is a damn sight more efficient than a single loco.)

 

[edwin_m]

The thermal energy required to raise water temperature from ambient to boiling point - although necessary - is effectively "waste" when it comes to moving a train.. The only "useful" energy could be regarded as that needed to convert liquid water (at boiling point) to high pressure steam - since that is what is required to move a steam loco and its train. .

That's right, but it should all be wrapped up in the way you calculate efficiency. You should take the total energy output at the drawbar divided by the total coal used for a steam loco operating a certain diagram, from cold boiler back to cold boiler, and compare it with the equivalent diesel figure. It's not easy - and some steam loco enthusiasts fiddle the figures by measuring only the coal consumption at a specific speed and power output for a specific time, which ignores all the wasted heat you are talking about. Of course electric traction has one fundamental advantage over both diesel and steam, which is that you can use regenerative braking to recover part of the kinetic energy put in when you accelerate the train and part of the potential energy when you climb a gradient.

To complicate things further, I believe steam engine fires were often left burning overnight when they were to be used the next day. That would remove the energy/emissions needed to heat the water in the boiler, but at the cost of extra emissions from keeping the fire burning.

The problem with electric traction is the embedded carbon generated by the construction/reconstruction of the railway required to install the OLE and distribution gear. Electricity also still needs to be generated somewhere, regenerative braking just tops up, and the UK's mix isn't anywhere near net zero yet (although I do accept that a power plant, even coal-fired, is a damn sight more efficient than a single loco.)

I suspect the embodied carbon in the construction is fairly small compared to the entire lifecycle, and recycling rates for steel and copper are pretty good. Also electric traction can practicably be powered from any known source including renewables, so can more easily be adapted when new and better sources become available. Diesels are limited to, er, diesel fuel or biofuel equivalents, and steam is limited to coal or can use oil-derived fuels rather less efficiently than a diesel.

 

[Jozhua]

Late steam and diesels almost certainly have had impacts in reducing emissions.

If you compare the efficiency of a diesel train to the many private car journeys it prevents from happening, you could imply from this that diesel trains have actually reduced emissions.

The primary benefit of electrification environmentally, is the operational and service benefits it brings, reducing the need for road travel.

In terms of tailpipe emissions, diesel trains almost certainly will surpass steam in time, but they are obviously going to be more efficient. Their biggest saving though, similar to electrification, is the operational benefits they bring to the railway, making it more competitive with road traffic.

 

[Sm5]

At least Volcanic ash is fertile, coal dust doesn't even give you that compensation.

In Germany up the Mosel river wine growers complained that after the 200+ steam movements a day ended, the taste and quality of the wine on the slopes above the line changed.